The OWA team has added a “Teams meeting” toggle in the new meeting item, as a preview feature. If you’d like to try it out, please turn on ""the new Outlook" toggle in the upper right corner. We’ll set this to completed once it’s fully released by the OWA team.

also , While in a call, add another person to the call
Reopening previous UserVoice post per request of MS Support:
https://microsoftteams.uservoice.com/forums/555103-public/suggestions/16952083-while-in-a-call-add-another-person-to-the-call"While in a call, you should be able to add another person (or more than one) to the call, to instantly create a group call. Similar as in Skype by clicking the "+" button."
This is NOT completed - this feature, as well as various other features (such as Delegate Call-As) are not available in PSTN calling/Calls tab, only Teams-to-Teams calling (via the Chat tab).
These features have been marked as completed in the UserVoice as well as the roadmap but that is not correct.